I think it could be interesting to have a some-what more in-depth stamina system with various survivors having different levels of stamina. As in some having multiple dodges or less based on the specific characters and their endurance level.
I know its obviously something that would be very hard to balance with the way levels are designed but I think it would be interesting for things like running, jumping gaps and hanging off ledges to (slowly) deplete the bar. It would probably need a lot of tweaking but I just find it interesting that every character is pretty much a parkour expert never getting tired or dropping after hanging off a ledge for longer than a few minutes.
Obviously don't want to take away player agency when it comes to certain things, perhaps instead it could be a negative trait for certain survivors or a curveball / effect when people are tired? I also think stealth and sneaking speeds could be higher or lower depending on the survivor as well.
I only say this after sort of cheesing specific levels, running back and forth over a hole, dropping the zombies inside where they can't reach me, though I understand these systems could potentially lead to frustrating situations that make people want to alt-F4.